TrigValTools: update and cleanup ignore list in rootcomp

Cleanup the histogram ignore list in rootcomp.py, which still contained a lot of obsolete rules from Run-1&2. Also remove ignore rule for "ResultsSizeByteStream" as the relevant ROOT bug has been fixed (ATR-21755) and add a "Random" histogram to the ignore list (ATR-24101).

Tested with the trigger ART tests that have a "required" RootComp step:

INFO     The following 6 tests will be executed:
INFO         test_trigP1_CalibPeb_build.py
INFO         test_trigP1_CalibPeb_concurrent_build.py
INFO         test_trigP1_CalibPeb_highForkAndMT_build.py
INFO         test_trigP1_HelloWorld_runStopRun_build.py
INFO         test_trigP1_magFieldToggle_build.py
INFO         test_trigP1_v1PhysP1_noL1Sim_runStopRun_build.py